#langs-exp"kernel.rkt";; The posn struct for the teaching languages
(providestruct:posnmake-posnposn?posn-xposn-yset-posn-x!set-posn-y!posn#;(rename-out (posnposn-id)))
(structposn (xy) #:mutable#:transparent)
;; We define a separate function so tha it has the
;; name `make-posn':
(define (make-posnxy) (posnxy))